Timber Windows in the UK, Costs, Lifespan, and Maintenance

Timber Windows UK 2026 Complete Buyer Guide

If you are replacing windows in 2026, you are weighing cost, energy performance, and long-term value. Timber windows sit between budget uPVC and premium steel or aluminium, but the financial and thermal calculations are not always straightforward. This guide breaks down the published data on costs, U-values, lifespan, and regulations so you can compare like for like.

For a standard 1.2m x 1.2m casement window, timber costs roughly £800 to £1,200 fitted, making it the most affordable premium material, aluminium costs £1,200 to £1,800 and steel-framed (Crittall-style) starts around £1,800 to £2,400 (FENSA/Glass and Glazing Federation industry averages, 2026). Exact figures vary by region, glazing specification, and finish, but the relative order is consistent.

A steel-framed window costs roughly 60% more than a timber window of the same size, making timber the most affordable premium material

For a standard 1.2m x 1.2m casement window, published industry averages show timber at approximately £800 to £1,200 fitted, while steel (e.g., Crittall-style) starts around £1,800 to £2,400, and aluminium is £1,200 to £1,800 (FENSA/Glass and Glazing Federation cost guide, 2025-26). The price gap narrows if you specify complex opening mechanisms or heritage-style detailing, but timber remains the lowest-cost option among the three premium frame materials. These figures are industry averages; your specific quote will depend on your property size, access constraints, and glazing choice.

Timber windows achieve a U-value of 1.2–1.6 W/m²K, which meets 2026 Building Regulations Part L

A U-value measures how quickly heat passes through a window, lower numbers mean better insulation. Double-glazed timber windows typically achieve a centre-pane U-value of 1.2 W/m²K, and a whole-window U-value of 1.4 to 1.6 W/m²K, meeting the 2026 Part L target of 1.6 W/m²K for replacement windows (GOV.UK Building Regulations Approved Document L, 2026 edition). Triple glazing can lower the U-value to 0.8 to 1.0 W/m²K, but adds 20 to 30% to the frame cost (MCS register certification data for timber window systems, 2026). If you live in a listed building or conservation area, you may be exempt from the Part L target, but you should check with your local authority.

Softwood timber windows cost £600–£900 per window, while hardwood costs £900–£1,500

Softwood (typically Scandinavian redwood or spruce) is the most common and affordable choice for UK timber windows, priced £600 to £900 fitted for a standard casement (FENSA cost index, 2026). Hardwood (e.g., oak, sapele, or mahogany) is denser and more durable, costing £900 to £1,500 per window, with a lifespan of 40 to 60 years versus 25 to 35 for softwood (Timber Trade Federation durability tables, 2026). Hardwood windows also tend to hold paint or stain better over time, which can reduce the frequency of repainting.

Quick numbers

Timber windows offer the lowest embodied carbon of any frame material, at roughly 30–50 kg CO₂ per window

Embodied carbon is the total greenhouse gas emitted during a product’s manufacture, transport, and disposal. A standard timber window frame has an embodied carbon footprint of 30 to 50 kg CO₂e, compared to 120 to 150 kg for aluminium and 80 to 100 kg for uPVC (BRE Green Guide ratings; DESNZ/National Calculation Method data for window frames, 2026). Timber sourced from PEFC or FSC-certified UK forests can be carbon-negative when the carbon stored in the wood is factored in (Wood for Good lifecycle analysis, 2025 update). This makes timber the clear environmental choice among window frame materials, especially if you are aiming to reduce your home’s whole-life carbon footprint. how to reduce your home’s carbon footprint through windows and doors

All timber windows sold in the UK must carry a BSI Kitemark or UKCA mark and be installed by a FENSA-registered or Certass-certified installer

The BSI Kitemark (or UKCA mark post-Brexit) certifies that the window meets British Standard BS 6375 (performance) and BS 7412 (timber window specification) (GOV.UK Product Safety for Windows page; BSI Kitemark scheme, 2026). Installation must be by a FENSA-registered or Certass-certified installer to comply with Building Regulations Part L and to self-certify the work (FENSA registration criteria; GOV.UK Building Regulations compliance guidance, 2026). For timber windows specifically, ask for proof of FSC or PEFC chain-of-custody certification for the timber used (FSC UK; PEFC UK, 2026). Without these marks, your installer cannot self-certify, and you will need to pay a building control body to inspect the work.

A timber window costs roughly 30% more than a uPVC equivalent but saves money over its full lifespan due to longer service life and lower replacement frequency

A uPVC window costs £400 to £600 fitted and lasts 20 to 25 years; a softwood timber window costs £600 to £900 and lasts 25 to 35 years (FENSA cost guide; BRE lifespan data for window materials, 2026). Over 50 years, timber windows can require one replacement versus two for uPVC, making the lifetime cost similar or lower. Hardwood timber windows (40 to 60 years) can last the life of the building with proper maintenance, eliminating replacement costs entirely (Timber Trade Federation durability data, 2026). If you intend to stay in your home for more than 20 years, the upfront premium for timber is likely to pay back through avoided replacement costs. uPVC vs timber windows lifetime cost comparison

Timber windows require repainting or re-oiling every 4–6 years, adding £50–£100 per window in maintenance costs

Microporous paint or stain should be applied every 4 to 6 years to protect the timber from moisture and UV damage; oiled finishes may need reapplication every 2 to 3 years (British Woodworking Federation maintenance guidelines, 2026). Professional repainting of a standard casement window costs £50 to £100 per window; DIY costs roughly £10 to £20 in materials (Checkatrade average cost data for window painting, 2026). Neglecting maintenance can reduce a timber window’s lifespan by 10 to 15 years (Timber Trade Federation care and maintenance advice, 2026). If you are not prepared to repaint every few years, or to pay someone to do it, timber may not be the right choice for you.